It spread Anglo-European culture across the nation and caused trade to flourish, but the story of the Chinese labourers who built the track has largely been forgotten.
Did Vikings find their way to a remote part of Oklahoma? Some in a small community believe so, thanks to controversial runic carvings found in the area.
The US island that nearly ignited a war bbc.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from bbc.co.uk Daily Mail and Mail on Sunday newspapers.